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Discussion Starter #1
When I start up the car after using the A/C there is this very loud and noticeable noise that sounds like....well....I don't know how to describe it. It sounds like a jet engine turbine starting up or a warble type noise. It goes away after a few seconds.

This has been happening for a while. And not all the time.

It seems like it's always something with my car.
 

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Check if you're running low on any fluids. Not too long ago my car was squealing, but it's all fixed.
 

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No, that is actually very normal. You cant expect the car to generate power for your A/C while just idling normally? it needs more power in order to put out the cold air. i dont know the details to explain everything specifically, but i can tell you its just the engine working a bit harder to put out the cold air for ya buddy.

what i CAN tell you though, dont start the car with the A/C turned on when ur car's not warmed up, like in the morning.

dont worry bout it,
-Aaron :p
 

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That made more sense. Having your A/C on before have your car warmed up would be a bad idea, I think. Take his word for it. I'm not an IS 300 driver, just a fan of the car. But I'm getting one! ;D
 

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I've started the car with A/C on before... and it hasn't caused any problems. But I do hear a "mechanical noise" when the compressor is engaging and starting up. Maybe that's what you are hearing?
 

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Crester said:
I've started the car with A/C on before... and it hasn't caused any problems. But I do hear a "mechanical noise" when the compressor is engaging and starting up. Maybe that's what you are hearing?
What he said....I think that sound is pretty common among IS's. Mine does it too......
 

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I just read in the Chicago Tribune car section recently that starting your car with the A/C on really isn't bad for the car.
 

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Was there any research or reason that they provided? The concept only makes sense, that when you car is slowly reaching normal temperature, to not put extra stress in it.

How bout we knock u out of bed at 5 am and tell u to start runnin laps within getting ready or stretching or warmin up? imagine how the car feels.

also, i read moses parted the red sea...did he? none of us know.

-Aaron
 

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yea dude dont worry, its all normal. unless you start your car and its that major squeeling, its nothing to worry about...its just the engine at work mang ;]

-Aaron
 

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Isn't it funny how we worry about every little sound our cars make? If we were driving a kia or something... we'd just be happy if the car didn't break down on our way to work! :lol:
 

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onyxaltezza said:
Was there any research or reason that they provided? The concept only makes sense, that when you car is slowly reaching normal temperature, to not put extra stress in it.

How bout we knock u out of bed at 5 am and tell u to start runnin laps within getting ready or stretching or warmin up? imagine how the car feels.

also, i read moses parted the red sea...did he? none of us know.

-Aaron
I don't remember the reason provided, but it is in a column by a master mechanic.

BTW, I happen to be an avid runner and cross country coach, so actually, I would do quite fine getting woken up at 5 am to run laps without stretching! Maybe the Lexus is the same way! :bigSmile:
 

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I really don't see why having the A/C on while starting the car would hurt the engine anyways.
 

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Crester said:
I really don't see why having the A/C on while starting the car would hurt the engine anyways.
That's exactly what the person writing into the column was asking...if it hurt the engine at all. The reply was no, it doesn't. I remember my ex-wife always nagging me to (among almost everything else in the world ;) ) turn off the A/C before turning off my previous car because it hurts the engine to start it up with it on, so I got in the habit of doing that until I read the Trib article. Now I don't worry about it much, though I usually do shut it off anyway out of habit. I think it had something to do with earlier engines in cars, and it did make a difference to start it with the A/C on at some point in time, but not today.
 

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I usually turn off my A/C... but that's to avoid being blasted by air unexpectedly when I turn on the car.
 

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Discussion Starter #17
alright then, if it's no big deal I got nothing to worry about.

Thanks guys.
 

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the compressor kicking in is making that sound.

the current the compressor draws to START UP is pretty high, and requries quite a substantial amount of your total battery ouptut. Your battery has not been charging when you first start up your car in the morning.

Infact, it has been slowly discharging, and a high current load such as a compressor kicking in will drain your battery quicker . add to it any ICE that starts up on ignition, and you have crazy amounts of excess load on the battery.

Let the alternator start providing a charge current to the battery , before you kick in any extra load. This applies to heavy ICE usage as well. heavy duty batteries such as the Optima Red Tops will help overcome this slightly, but you cant fight the simple laws of electricity.

And oh.. if you think your alternator is dead/dying since your battery is ok, but cant hold a charge, make sure you DO NOT TURN ON a/c or even the damn radio, adn ESP. the HID's ( unless needed! ).

I had my alternator in my previous junkbox, a 95 altima die on me while driving down I-95, and the car slowly started killing off the electronics... i barely made it off the ramp before it shut down totally and killed current to the fuel pump relay.

so yes, wait until the car is on, before hitting A/c ,.. no need to wait any longer, but honestly, you would be better airing out the car for a couple of minutes anyways!

Hope this helps. :)
 

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But I was thinking... technically the A/C does come on AFTER the engine starts anyways. It's not as if the A/C kicks in the instant you turn the key to start the engine.
 

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I've noticed that my A/C compressor actually starts kickin in 10 seconds or so after the car starts up so that it doesn't strain the car before it gets up an running.
 
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